Fluorinated compounds show high lubricity, water/oil repellency, etc. and are thus useful for surface treating agents. Such surface treating agents impart water/oil repellency to a substrate surface, thereby making it easy to wipe off stains from the substrate surface with improved stain removability. Among such fluorinated compounds, a fluorinated ether compound having a poly(oxy perfluoroalkylene) chain, wherein an ether bond (—O—) is present in the perfluoroalkylene chain, is particularly excellent in the fat and oil stain removability.
Surface treating agents containing such a fluorinated ether compound are useful in applications which require long-lasting water/oil repellency that withstands repeated rubs by fingers (abrasion resistance) and long-lasting ease of removal of fingerprints from a surface by wiping (fingerprint stain removability), e.g. as a surface treating agent for a member constituting a surface to be touched by a finger, of a touch panel.
Introduction of a hydrolyzable silyl group to the end of a fluorinated ether compound imparts abrasion resistance to a surface layer formed on a substrate through formation of chemical bonds between the fluorinated ether compound and the substrate. A fluorinated ether compound having three hydrolyzable silyl groups at both ends via a branched structure of pentaerythritol was proposed with the aim of forming a surface layer with excellent abrasion resistance (Patent Document 1).